Well thats sound a big replacement. What I recommend you is to post as Wanted on
www.cloudynights.com there are many ppl that offer the whole mount, you just need to swap OTA (optical tube assembly). I found my hand controller on that website by posting. The same person had the whole mount except the controller I bought from him. I don't know about the dec motor but it worth to ask in that website. If your interested in the mount. His name is Brian you can ask him if he still has that mount, his email is:
cbrianbatey@comcast.netgood luck.
Att
Jose